The suckers as the bottom typically belong to the rootstock and so the fruit is inferior. When i cut scion wood i cut it from the top in areas i know fruit the desired type of fruit. To answer your question yes you can graft the scion on a dwarf rootstock. This is one method Whip and Tongue techniques .Many times people use grafting tools the first time they graft as it makes joining the scion wood from your tree onto the rootstock you want to graft to easier Italian Grafting Tools: Grafter's Tool, Arborist's Grafting Tool